This invention pertains to an attachment to a camera lens for providing a weak diffuse illumination upon the film.
The procedures of "pre-flashing" photographic film before it is exposed to the desired image, or "post-flashing" the same after it has been exposed has long been known.
In addition, certain relatively involved auxiliary optical systems attached to a camera or a printer are also known.
The U.S. Pat. No. 2,556,307, to J. B. Walker, of June 12, 1951 discloses a light box containing a lamp or lamps and a 45.degree. half-silvered mirror to direct flashing light upon a film at the same time it is also exposed with the desired image. The light box is attached to the front of the camera. The box is bulky. The light that forms the desired image is undersirably decreased by the presence of the half-silvered mirror in the main optical path.
U.S. Pat. No. 2,352,914, to G. F. Rackett, of July 4, 1944 provides an additional light beam (2) for simultaneously flashing or separately flashing a positive film in the process of color printing. This light beam also enters the main optical path by means of a half-silvered mirror disposed at 45.degree. thereto.
This arrangement, of course, is part of a positive color printing apparatus.
U.S. Pat. No. 1,598,746 to G. Roes, of Sept. 7, 1926, provides an incandescent lamp (14) on an arm in front of a still-object-photographing camera. This bare lamp is swung into the main optical path in front of the camera after the image exposure is made for a period of from ten to thirty seconds. This gives post-flashing. According to the patent it takes the palce of a large white illuminated "flash sheet".
This arrangement and the method of use are obviously different from the subject invention.